Block-signal system.



' PATENTBD APR. 2, 1907.

5. F. BLISS. BLOCK SIGNAL'SYSTEM.

APPLICATION FILED SBPT.19,1906.

2 SHEETS-SHEET 1.

- Inventor" :1

'Elr her F. Bliss,

No. 848,959. PATENTED APR. 2, 1907.

E. F. BLISS. BLOCK SIGNAL SYSTEM.

APPLIOATION FILED SEPT. 19. 1906.

' 2 SHEETS-SHEET 2.

Witnesses: Inventor:

, Elmer-F. Bliss,

unrrnn STATES PATENT onnion.

ELMER F. BLISS, OF SCHENEOTADY, NEI/V YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

BLOCK-SIGNAL SYSTEM,

No. 848,95Q.

Specification of Letters Patent.

Patented April. 2, 1907. I

Application filed September 19, 1906. Serial No. 336,209.

To all whom it may concern.-

Be it known that I, ELM R F. BLIss, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful.

one block passing into another block while allowing the power-current to pass.

My invention consists in making the rails ,conductively continuous for both power and signal currents and employing sources of high-frequency alternating current connected atintervals across the track-rails, adjacent sources being of difierent phase, with signal-controlling means connected between the sources responsive only tothe resultant current from both adjacent sources, so that if either source fails the signal for the tracksection between the sources will be .put at danger.

My invention further comprises a novel relav construction es ecially applicable. where relays are connected in pairs across the rails; as in my present system.

-My invention will best be understood by reference to the accompanying drawings, in which- Figure 1 shows diagrammatically'a blocksignal system arranged'in accordance with" my invention. Figv 2 is an explanatory diagram. Fig. 3 shows a side elevation of a pair of relays arranged in accordance with my invention, and Fig. 4 shows a plan view of the same in cross-section on the line 4 4 of Fig. 3.

Referring first to Fig. 1, A represents the track-rails of an electric railway, which are made conductively continuous for all currents throughout their length. B represents the third rail or other su ply-conductor for the power-current, which 18 connected to one.

terminal of the power-generator C. This generator may supply either direct or lowfrequency alternating current. Its other Y tion of Fig. 2.

terminal may be connected to the track-rails A through a differential choke-coil c.- D represents a high-frequency three-phase generator, which supplies current for the signal-circuits through the three-phase line-wires (1!, d and (i E E 850., represent transformers which have their primaries connected to the line-Wires and their secondaries to the track. 1 Small resistances e and 6 may be employed in the secondary circuits of the transformers in order to prevent an excessive flow of power-current through the secondary windings. It will be noted that adjacent transformers are supplied from different phases of the enerator D. F and F represent a pair oireIays, which are shown as of the well-known induction-type, each hav-- ing one winding connectedacross the track through a'resistance f for the purpose of limiting the flow of power-current through the relay-windings. The other winding of each relay is supplied independently of the rail circuit from the line-wires, and it will be noticed thatthe two relays are connected to difierent line-wires. The relay F has a winding connected to the same phase as transformer E, while the relay F has its corresponding winding connected to the same phase as the transformer E". The "two reays jointly control the signal G, their c0ntacts being connected in series with the sig- I nal-operatmg mechanism and with I each I other.

The eiiect of the currents of diflerent phase on the relays will be evident from a considera- In this figure if 0 representsthe base of the current su plied to the rails by the transformer E and i 0 represents the current supplied to the rails by the transformer E 0 and 0 being one hundred and twenty degrees apart, then the current.

throughfthe track-windings of the relays F and F will be represented by 0 dis laced sixty degrees from both" 0 and 0 ow if the current hrough the second winding-of re' lay Fbe also represented'bythe line 0 and the current through the secondwinding of relay F by 0 then it will beseen'that the rein each of the other two re ay-winding1s, ro-- duces a torque in each relay due to. the's mty' degrees phase displacement. Now if elther sultant current 0 coactin 'v't'lth'the current transformer should fail'as, for instance. be-F cause of a broken rail orbecause of being shunted by a trainone of the component currents in the rail will disappear and the current in the track-windings of the relays will be shifted into phase with the current in the second winding of one of the two relays. This relay will consequently drop its armature, allowing the'si nal Gto go to danger, while the-other re ay still has its normal 1:) .torquethat is, both relays are responsive simultaneously'only to the resultant current fromboth transformers E and E and one of them will drop its armature upon-the failure of either of its transformers.

r 5 The operation of ilie system is then as follows: With a train at H moving in the direction of the arrow the rails will be shortcircuited between the transformer E andrelay F". The current flowing through the track- '20 windings of the two relays consequently comes wholly from transformer E so that there is no phase displacement between the currents of the relay F 7 Thisrelay consequently drops itsarmature. The circuit of i 4; s1 nal G is consequently broken, and though re ay F still holds up its armature, due to the phase displacement of the currents in its windings, it will drop its armature sometime 7 before the train reaches it and will not pick up until the train has passed transformer E 5 have pulled down the voltage of transformer E? suificiently'to put relay F or F or both, at dan er. Signal G will consequently go to anger a short time before signal G clears. he amount-of this overlap depends upon the regulation of the transfor impedance of the rails, and the resistance of the track-winding circuit of the relays, and I by employing a high-frequency alternating, current to which the rails offera high impedance and by properly designing the trans formers -and relaysthis overlap may be practical operation; I Inxplace of' employing a separate trackwinding for each relay aneconomy in power and in material may be secured by emloy ing a single track-winding common to hoth relays, as shown in Figs. 3 and 4." In these.- liguresfl and I represent two pivotedcon made so smallas to be: of no importance, in-

- temfor the signal-circuits in'wliic rents supplied to the rails by adjacent trans- 9o Signal G is consequently at danger responsive to control a signal only to currentof thedphase -of the "resultant current from both a in pairs at points between the sources, each ducting disks, which form the 'secondarymembers of the relays and carry the relay-- contacts. These contacts are connected in se ries, as"has been heretofore explained. l'lwo C -shaped cores J are placed on opposite sides of the two disks, with coils K on each core.

These coils are connected in series or in parallel with each other and to the track, and thus form a single winding which is in inductive relation to both members I and 1 The relay F has a C-shaped core L on each side of j the cores J, and on each of these cores isplaced a coil M, whichsuppliedwith cur- 4 rent independently of the rail-circuit, the

two coils being reversely connected, so as to produce a torque in the same direction. The relay F is similarly arranged. With this construction the current induced in eachdisk by the single windingfK cooperates with" the current induced by the other winding of each relay, so as to produce the necessary 8511 torque. By employing a single winding economy of current and power is obtained.

Although I have shown a threehase syslithe curformers are one hundred and twenty degrees out of phase, it is obvious that other numbers of phases in -which' adj acent' source's differ in phase by a'different angle may be employed.

Consequently I do not desire to limit mys lf to the particular arrangement sh What I claim as new, and-'desireto 'seoure by Letters Patent of the United S' -t s-- .-1. In confbination with an eledt having both rails 'conductivelyc iniloustoo for all currents, sources of alternating'c'urrent,

connected across the track-rails" atin'tervals, adjacent sources being of-diiferent phase, and. signal-controlling means connected. across the rails at points between the sources and acent sources. 2. In combination with an electric railway having both rails conductivelycontinuous for all currents, sources of alternating current connected across theirack-rails at inter-- vals, adjacent sources being of different phase, and signal-controlling relays arranged relay having two coacting windin 's, QfififQQ i nected across the track-rails and traversed by the resultant current-'from 'both. 'djacnt sources, and the othe plied end-' ently of' the railswith current of the pi oper hase for producing an efiective torqnein lioth relays simultaneouslyonly in honjnnd tion. said resultant current.

3. In combination with an electric railway.

having bothrails conductively continuous for all currents, sources of alternating current connected across the track-rails at inter- ,vals, adjacent sources being of different phase, and signal-controlling relays connected across the track-rails in. pairs at points bewith current of the same phase and arran tween the sources, the relays being respon- 'sive simultaneously only to current of the phase of the resultant current from both adacent sources.

4. In combination With an electric railway having both rails conductively continuous for all currents, two sources of high-frequency currents of different phase connected across the rails a distance apart, a block-signal for the portion of track between said sources, and signal-controlling means connected across the rails at a point between said sources ed to put said signal at danger upon a failure 0 current from either of said sources,

5. In combination with an electric railway havim both rails conductively continuous for alI currents, two sources of alternating currents of the same frequency'but different phase connected across the rails a distance apart, two relays connected across the rails at a point between said sources responsive simultaneously only to the resultant current from both sources, and. a signal controlled by the joint action of said relays.

6. In combination with an electric railway havin both rails conductively continuous for al currents, two sources of alternating currents of different phase connected acresss the rails a distance apart, and a signal-controlling relay of the inductive type having two coacting windings, one connected across the rails at a point between said sources and the other supplied independently of the rails as that supplied by one of said sources to the rails.

7. In combination with an electric railway having both rails conductively continuous for all currents, two sources of alternating currents of different phase connected across the rails a distance apart, two relays of the inductive type each having two coacting windings, one windingof both relays being connected across the rails at a oifitbetween said sources, and the other. windings of the relays being supplied independently of the rails with currents corresponding in phase to the currents supplied to the rails by said two mg connected across the trackrails and each employing the having a second winding sup lied with curr rent independently of the m1 circuit and or each other. 9. In anelectric railway employing the rails as return-conductor for the power-current, a pair of relays having a common. windingconnected across the track rails and each having a second winding sup lied with current independently of the rai -circuit and of each other, and a signal controlled by said relays'jointly.

10. In an electric railway employing the rails as return-conductor for the power-current, a source of alternating current connected to the track-rails, a pair of relays each comprising a short-circmted conducting member, 'a winding connected across the track-rails in inductive relation to both members, and an independent winding for each relay coacting Withthe track-winding and suplplied with alternating current independent y of the rail-circuit. V

11. In an electric railway employing the rails as return-conductor for the power-current, a source of alternating current connected to the track-rails, comprising a short-circuited conducting mem her, a winding connected across the trackrails in inductive relation toboth members,

an independent winding for each relay coacting with the track-winding and supplied with alternating current independently of the rail-circuit, and a signal controlled by said relays jointly.

Inwitness whereof I have hereunto set my hand this 18th day of September, 1906.

ELMER F. BLISS.

a pair of relays each. 

